1. Field of the Invention
The present invention relates to a solid-state imaging apparatus and an imaging system.
2. Description of the Related Art
A back-side illumination solid-state imaging apparatus generally includes a semiconductor layer that is thinner than in a front-side illumination solid-state imaging apparatus. For this reason, incident light (especially, light having a long wavelength) may transmit through the semiconductor layer without being sufficiently absorbed. Each of Japanese Patent Laid-Open No. 2010-118412 and U.S. Pat. No. 7,755,123 discloses a structure including a reflection portion that reflects light that has transmitted through a semiconductor layer (semiconductor substrate). According to the structure of Japanese Patent Laid-Open No. 2010-118412, a microlens 110 condenses incident light in a photoelectric conversion portion 130, and a reflection portion 150 condenses reflected light in the photoelectric conversion portion 130. According to the structure of U.S. Pat. No. 7,755,123, light components L1 and L3 (vertical incident light) that have vertically entered the apparatus are condensed on a surface 126 of a reflection portion 128.
In the solid-state imaging apparatus, interconnections for power supply, pixel driving, or signal read are provided on the obverse surface side of the semiconductor layer. For this reason, instead of providing a reflection portion having a large area on the entire surface, a plurality of reflection portions having small areas are preferably divisionally arranged. However, when the plurality of reflection portions having small areas are provided, gaps are generated between the reflection portions.
The condensing position of light (oblique incident light) that has obliquely entered the solid-state imaging apparatus shifts from the condensing position of vertical incident light. For this reason, when reflection portions having small areas are formed, the oblique incident light partially leaks to the gaps between the reflection portions. Since some light components are not reflected by the reflection portions, the light sensitivity may lower.